Undergraduate dental students' perceptions of dental pain in children - A grounded theory study.

INTRODUCTION: There is an underuse of pain management strategies in dental care for children, possibly owing to perceived stress and discomfort when treating children, which has also been reported by dental students. The aim of this study was to explore how undergraduate dental students experience and understand pain related to dental treatment in children. MATERIALS AND METHODS: Interviews were held with 21 Swedish dental students, from 3 dental schools, all in their final 2 years of education. The interviews were transcribed verbatim and analysed according to Grounded Theory. RESULTS: A core category, seeking guidance to avoid pain, was identified and related to 6 conceptual categories. The students used different strategies to manage pain prevention in child dentistry and to become skilled dentists. They described high levels of stress, as well as having high expectations on themselves when treating children. The stress led to a surface learning approach, something the students were not fully aware of. CONCLUSION: All children should have the right to be ensured optimal pain prevention in dental care. The basis for this is laid during undergraduate education. Thus, pain management in child dentistry is an area in need of special attention in this respect. The academic staff has an important role in supporting their students in their process to gain an identity as professional dentists. To ensure that students incorporate an understanding of the importance of pain prevention when treating children there is a need to create more integration between theory and clinical training in undergraduate education.

Effect of production method on surface roughness, marginal and internal fit, and retention of cobalt-chromium single crowns.

STATEMENT OF PROBLEM: New production methods have been developed for metal-ceramic restorations. Different production methods may show different surface roughness and fit, which may affect retention and long-term success. PURPOSE: The purpose of this in vitro study was to examine 3 different production methods with regard to surface roughness, marginal and internal fit, and retention of cobalt-chromium alloy single-crown copings. MATERIAL AND METHODS: A master abutment of a premolar mandibular tooth preparation with 4-mm height and a 0.6-mm deep 120-degree chamfer finish line with a 12-degree angle of convergence was replicated in die stone and scanned. Thirty-six cobalt-chromium alloy copings were produced using 3 different production techniques. Twelve copings were produced by laser-sintering, 12 by milling, and 12 by milled wax/lost wax. The surface microstructure of 2 copings in each group was analyzed using interferometry. The remaining 10 copings in each group were used to evaluate marginal and internal fit by using an impression material replica method, and retention was evaluated by using a uniaxial tensile force pull-off test. The copings from each test group were cemented with zinc phosphate cement onto resin abutments. Statistical analyses of differences in marginal and internal fit were performed using 1-way ANOVA and the Mann-Whitney U test. Differences in surface topography were analyzed with the Kruskal-Wallis and Mann-Whitney U tests for nonparametric data. Differences in retentive values were analyzed using the Mann-Whitney U test for nonparametric data (all α=.05). RESULTS: Differences in surface microstructure were seen. The laser-sintered copings showed increased surface roughness compared with milled and milled wax/lost wax copings. Differences in marginal and internal fit were noted. Laser-sintered showed significantly smaller spaces between coping and abutment than milled wax/lost wax copings (P=.003). At the margins, laser-sintered copings showed significantly smaller spaces than either the milled wax/lost wax group (P=.002) or the milled group (P=.002). At the chamfer, laser-sintered copings showed significantly smaller spaces than milled wax/lost wax copings (P=.005). At the center of the axial walls, laser-sintered copings showed significantly smaller spaces than those in the milled wax/lost wax (P=.004) and milled copings (P=.005). No significant differences were noted between milled and milled wax/lost wax copings (P>.05). No significant differences were detected regarding retentive forces in the pull-off tests (P>.05). CONCLUSIONS: Laser-sintered Co-Cr crown copings showed increased surface roughness and better internal and marginal fit than copings produced by milling or milled wax/lost wax technique. However, the crown pull-off tests did not reveal any significant differences.